1. Technical Field
The embodiments herein generally relate to prosthetic devices, and, more particularly, to an artificial intervertebral disc used for stabilizing vertebral bodies.
2. Description of the Related Art
The human spine contains multiple flexible levels of joints comprising adjacent vertebral bones. The joints comprise two-part intervertebral discs consisting of a nucleus and an annulus. The joint system allows for both motion and stabilization of the spinal column with the disc providing motion and cushioning to the joint. The joint is subjected to varying loads, which, over time, can result in mechanical breakdown (i.e., fatigue and fracture, etc.) of the disc (i.e., disc degeneration) due to a variety of reasons including aging, damage due to excessive loading, trauma, and other anatomical issues. Severe joint degeneration and failure may require medical intervention including implanting artificial intervertebral discs to cure the deficiencies of the spinal column.
Such a surgical procedure is complex and generally involves fusing the damaged section of the spinal column into a single mass of bone. While this treatment generally alleviates the pain associated with damaged joints the surgical fusion may result in unintended complications including the body rejecting the prosthesis, incorrect alignment, or mechanical breakdown of the artificial discs themselves. Furthermore, because one level of the spine is operatively connected to the other adjacent levels of the spine, biomechanically altering one level may eventually alter the alignment of the adjacent levels requiring future surgery.
Accordingly, it is one objective of intervertebral disc replacement to provide a prosthetic disc that combines both stability to support the high loads of the patient's vertebrae and flexibility to provide the patient with sufficient mobility and proper spinal column load distribution so as to not negatively impact the adjacent levels. Various types of artificial intervertebral discs have been developed for replacing a part or all of a removed disc. However, most artificial discs used as a substitute to an intervertebral disc typically only allow and control one of two types of motion: (i) rigid rotation/translation, or (ii) soft uncontrolled spring/damping. Therefore, there remains a need for a novel artificial intervertebral disc capable of controlling both types of motion.